Sewn closure square bottom bag



Oct. 2 1, 1969 5. COVERSTQNE ET AL 3,473,724

SEW CLOSURE SQUARE BOTTOM BAG 4 Sheets-Sheet 1 Filed Jan. 151, 1968 FIG.

FIG. 3

0 9 s. L. COVERSTONE ET AL 3,473,724

v snvm CLOSURE SQUARE BOTTOM BAG Filed Jan. 31, 1968 4 Sheets-Sheet 2 I LAsm 1 FIG. 6

Oct. 21, 1969 s. L. COVERSTONE ET AL 3,473,724

SEW CLOSURE SQUARE BOTTOM BAG 4 Sheets-Sheet 5 F11! Jan. 31, 1968 FIG. 7

FIG. 8

FIG.

Oct. 21, 1969 5, COVERSTONE ET AL 3,473,724

5mm CLOSURE SQUARE BOTTOM BAG Filed Jan. 31, 1968 4 Sheets-Sheet 4 nited States Patent l 3,473,724 SEWN CLOSURE SQUARE BOTTOM BAG Stephen L. Coverstone, 7010 Miami Ave. 23226, and Raymond K. Hughes, 225 Laburnum Ave. 23222, both of Richmond, Va.

Filed Jan. 31, 1968, Ser. No. 702,065 Int. Cl. B65d 31/08, 31/10 US. Cl. 229-58 8 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Both square bottom bags and sewn closure bags are well known in the art and individually have distinctive advantages. The present invention, by combining both types of bags into one, also combines the advantages of both types of bags.

Square bottom bags have been utilized to advantage because of easy stacking and the availability of butt printing. These are advantages not possessed by pinch bottom bags having pillow corners.

Sewn closure bags provide advantages not possessed by the prior art square bottom bags. The sewn closure is easy to open by simply pulling out the thread. By comparison, prior art square bottom bags, generally having pasted closures, must be torn to open. Tearing may also lead to contamination of the bags contents with paper fibersa disadvantage not occurring with sewn closures. Silicone coated paper bags must be scraped clean of silicone in the area of paste sealing, this step being unnecessary for the sewn closure. Further, where multiwall bags are provided with an inner plastic ply, heat sealing the inner ply leads to difficulties when employing a pasted closure. By comparison, an inner plastic ply is still easily heat sealed after providing a sewn closure.

Bags of the present invention possess not only all of the above advantages but are also easily manufactured by simple folding and one step sealing, which may be utilized not only to manufacture paper bags but also plastic, multiwall, and laminated bags, the latter two being any combination of paper, plastic and/or other known materials.

SUMMARY OF THE INVENTION The present invention provides a square bottom container which is foldable into :a flat condition when empty and has a parallelepiped-a1 shape when filled, the container comprising, when empty, a flattened tube having a front wall and a back wall connected by intermediate longitudinal side walls, a bottom panel integral with said back wall and closely adjacent at least part of the inner side of said front wall; and a seal connecting an edge of said bottom panel to an edge of said front wall.

Additionally, the present invention provides a method for producing a blank for square bottom containers com- 3,473,724 Patented Oct. 21, 1969 prising forming a flexible sheet material into a fiat tube having a front wall and a substantially parallel back wall connected by intermediate longitudinal side walls; insetting one end of said front wall a short distance in the longitudinal direction of the tube between the side walls; and providing fold lines in said tube which are located transverse said front wall and substantially parallel to and spaced a short distance from the inset end of said front wall, transverse each side wall and substantially perpendicular to said front wall and the fold line in said front wall, in each side wall in the shape of a triangle having its apex intersecting an intermediate point of the transverse fold line in each side wall and having its base substantially parallel to said transverse fold lines and intersecting the corner formed by said inset end of said front wall and each side wall, transverse said back wall and connecting respective ends of transverse fold lines in the side wall, also transverse said back wall and connecting respective ends of the bases of the triangles, and diagonal each side wall and connecting the ends of the fold line also transverse said back and a respective corner of each side wall.

The present invention also includes forming said blank into a square bottom container by folding said tube along the provided fold lines so that the apex of each triangle is substantially directed toward the apex of the other triangle, an outside portion of each side wall between a diagonal fold line and a respective triangle base abuts an outside portion of each side wall on the opposite side of said diagonal fold line, an inside portion of said back wall between the second transverse fold line and the end of said back wall abuts an inside portion of said front wall between said inset edge and said transverse fold line in said front wall; and securing in a fixed relationship at least part of said front wall to said back wall.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a gusseted tube provided with a first embodiment of a cutting pattern shown in phantom.

FIG. 2 is a perspective view of an individual bag formed in accordance with the cutting pattern of FIG. 1 and provided with fold lines and a top flap shown in phantom.

FIG. 3 is a perspective view of the bag of FIG. 2 during initial folding of the bottom assembly.

FIG. 4 is a perspective view of the bag of FIG. 3 during further folding of the botom assembly.

FIG. 5 is a perspective view of the bag of FIG. 4 during sealing of the bottom assembly.

FIG. 6 is a cut-a-away end view taken along lines 6-6 of FIG. 1 and FIG. 7 of a rnultiwall bag.

FIG. 7 is a perspective view of a gusseted tube provided with a second embodiment of a cutting pattern shown in phantom.

FIG. 8 is a perspective view of the second embodiment of an individual bag formed in accordance with the cutting pattern of FIG. 7 and provided with fold lines and a top flap shown in phantom.

FIG. 9 is a perspective view of the second embodiment of the bag of FIG. 8 during initial folding of the bottom assembly.

FIG. 10 is a perspective view of the second embodiment of the bag of FIG. 9 during further folding of the bottom assembly.

FIG. 11 is a perspective view of a first alternative to the second embodiment of the bag of FIG. 10 during completion of the folding of the bottom assembly.

FIG. 12 is a perspective view of the sealing of the bottom assembly of the first alternative of FIG. 11 to the second embodiment of the bag.

FIG. 13 is a perspective View of a second alternative to the second embodiment of the bag of FIG. 10 during completion of the folding of the bottom assembly.

FIG. 14 is a perspective view of the sealing of the bottom assembly of the second alternative of FIG. 13 to the second embodiment of the bag.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, prior to cutting individual bags from a part of a continuous tube, which may be either paper, foil, or plastic or multilayered combinations thereof including larninations, the tube is preferably provided with gussets. A cutting pattern is shown on the tube in phantom outline. In accordance with this pattern tube 1 may be divided along lines 2 into individual bags 3 of any desired length. Each bag has a front wall or face 4, side walls 5 and a back wall 6. Each side wall 5 is given the shape of bellows or gussets by means of fold line 7. In the cuting of bags 3 from tube 1, both or either top flap 8 and/or bottom flap 10 may be provided as desired as shown in phantom with dotted lines 9. Omission of bottom flap 10 results in the first embodiment of bag 3 as shown in FIGS. 2 to 5.

In FIG. 2 there is shown an individual bag 3 separated from tube 1. Optional top flap 8 is shown in phantom. This bag is provided with a number of fold lines in the end assembly 11. Among the fold lines is line 12 which is transverse front wall 4 and parallel to inset edge 13. Connecting with the ends of and perpendicular to transverse fold line 12 are fold lines 14, which are transverse each side wall 5. Intersecting about the mid point of each fold line 14 are fold lines forming the apex of isosceles triangle 15 having substantially equal sides 16 and a fold line base 17 substantially parallel to fold line 14. Base lines 17 also intersect the ends of inset edge 13. Diagonal each side wall 5 and connecting the end of base 17 which does not intersect inset edge 13 with an opposite corner of side wall 5 is fold line 18. Connecting the ends of fold lines 14 is fold line 19 which is substantially parallel to and aligned with fold line 12; connecting the ends of the base lines 17 is fold line 20 which is substantially parallel to and aligned with inset edge 13.

FIG. 3 shows the initial folding operation and forming of the bottom assembly 11 of the bag. In this folding operation, the gussets of side walls 5 are folded to lay in abutting relationship, and triangles 15' are arranged to have apexes substantially pointed at each other. The portions of the side wall around fold line 18 and base 17 are folded to provide gussets between back wall 6 and front wall 4.

As disclosed in FIG. 4, bottom assembly 11 is substantially completely folded by bringing bottom wall 6 into abutting relationship with at least a portion of top wall 4, thus exposing raw edges 21 which will eventually be sealed. The arrows in FIG. 4 indicate the direction of the final fold of the bottom assembly in order to facilitate sealing of raw edges 21.

The sealing of the bag with tape and stitching is shown in FIG. 5. This type of sealing is preferably used for paper bags, but where plastic bags are being made, heat sealing is more desirable. In the manufacture of multiwall or laminated bags having inner plastic plys, both a heat seal and sewn closure may be utilized.

FIG. 6 discloses a cutaway view of a representative multiwall bag having three outer plys of paper and one inner ply of plastic. In this type of multiwall bag, the plastic plys are heat sealed while the paper is sealed with stitching, alone, or including tape as shown in FIG. 5.

Of course, the layers of paper and plastic may be staggered in the bottom assembly so as to avoid bulk in the folds.

A second embodiment of the present invention is shown in FIGS. 7-14. The main difference between this embodiment and the first embodiment is the provision of bottom flap 22 which necessitates some changes in the cutting of bag 3 from tube 1. A cutting pattern is shown in phantom in FIG. 7 with dotted lines 23. Inset edge 13 of FIG. 2 becomes a fold line in the second embodiment of the bag.

A phantom top flap 8 in addition to bottom flap 22 1s shown in FIG. 8. When a bag is made with both flaps, it is desirable to make an adjacent bag from tube 1 which possesses neither a top flap nor botom flap. Otherwise, the provision of fold lines in the bottom assembly is substantially the same for the second embodiment as it IS for the first embodiment except for fold line 24 hingedly connecting bottom flap 22 to front wall 4.

Initial folding of end assembly 11 of the bag of the second embodiment as shown in FIG. 9 is substantially the same as initial folding of the end assembly of the bag of the first embodiment as shown in FIG. 3, except for the presence of bottom flap 22.

FIG. 10 discloses further folding of the bottom assembly of the bag of the second embodiment. The principal distinguishment of the second embodiment over the first embodiment is here more apparent as being the provision of bottom flap 22 which is subsequently disposed in alternative ways as shown in FIGS. 11 and 13. Thus, as shown in FIG. 11, flap 22 is simply folded over an integral portion of back wall 6 which now forms a bottom panel of the sack and is sealed with tape and stitching as shown in FIG. 12 or, where plastic is utilized solely as the material for the bag or as an inner ply, is preferably heat sealed, either solely or in addition to the sewn closure. It is evident that sealing is effected on an opposite side of the bottom bag as compared with the first embodiment as shown in FIG. 5.

FIG. 13 discloses a second alternative of the second embodiment wherein top flap 22 is tucked between front wall 3 and the portion of back wall 6 forming a bottom panel of the sack. As shown in FIG. 14, sealing may be effected by stitching, alone, or including tape, and/or by heat sealing in the case of plastic bags or plastic inner plys. Sealing is effected on the same side of the bottom of the sack as in the first embodiment of the bag shown in FIG. 5.

We claim:

1. A square bottom container which is foldable into a flat condition when empty and has a parallelepipedal shape when filled, the container comprising, when empty, a flattened tube having a front wall and a back wall connected by intermediate longitudinal side walls; a bottom panel integral with said back wall and closely adjacent at least part of the inner side of said front wall; a seal connecting an edge of said bottom panel to an edge of said front wall; and a bottom flap integral with said front wall which lies between and abuts at least part of said bottom panel and at least part of the inner side of said front wall.

2. The container of claim 1 wherein said seal comprises tape and stitching.

3. The container of claim 1 wherein said container is at least partly plastic and said seal is at least partly a heat seal.

4. The container of claim 1 wherein a top flap is provided integral with said front Wall.

5. A square bottom container which is foldable into a flat condition when empty and has a parallelepipedal shape when filled, the container comprising, when empty, a flattened tube having a front wall and a back wall connected by intermediate longitudinal side walls; a bottom panel integral with said back wall and closely adjacent each part of the inner side of said front wall; a seal con- 3,473,724 5 6 necting an edge of said bottom panel to an edge of said References Cited front wall; and a bottom flap which is integral with said front wall and overlaps said bottom panel which abuts UNITED STATES PATENTS at least part of said front wall. 590,559 9/1897 Appel 229-58 6. The container of claim 5 wherein said seal com- 5 1,298,252 3/1919 f 'y 22958 prises tape and stitching 3,204,856 9 965 Wlls n 22953 7. The container of claim 5 wherein said container is at least partly plastic and said seal is at least partly DAVID BOCKENEK Pnmary Exammer a heat seal.

8. The container of claim 5 wherein a top flap is provided integral with said front wall. 10 22953 55 

